C81.22
BillableMixed cellularity Hodgkin lymphoma, intrathoracic lymph nodes
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C81.22 an HCC code?
Yes. C81.22 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for C81.22
For C81.22 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C81.22 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C81.22 is the ICD-10-CM diagnosis code for mixed cellularity hodgkin lymphoma, intrathoracic lymph nodes. A type of Hodgkin lymphoma with mixed cellularity affecting lymph nodes in the chest area. C81.22 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).
Under the CMS-HCC V28 risk adjustment model, C81.22 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C81.22 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Verify the specific site of involvement is documented as intrathoracic (chest) lymph nodes. Because C81.22 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C81.22 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the specific site of involvement is documented as intrathoracic (chest) lymph nodes
- •Confirm the histological type is mixed cellularity and not another Hodgkin lymphoma subtype
Clinical Significance
Mixed cellularity Hodgkin lymphoma of intrathoracic lymph nodes represents mediastinal or other chest lymph node involvement by this subtype. While intrathoracic involvement is the hallmark of nodular sclerosis Hodgkin lymphoma, mixed cellularity can also present in the mediastinum, though less commonly. Distinguishing between subtypes at this location requires pathologic confirmation and has implications for prognosis and EBV association.
Documentation Requirements
- ✓Pathology confirming mixed cellularity subtype (not nodular sclerosis)
- ✓Chest imaging documenting intrathoracic lymph node involvement
- ✓Assessment for mediastinal bulk
- ✓B-symptoms assessment
- ✓Complete staging workup
- ✓Treatment plan
Commonly Confused Codes
- •C81.12 — Nodular sclerosis, intrathoracic: Far more common at this location; pathology must confirm mixed cellularity
- •C81.20 — Mixed cellularity, unspecified site: Use C81.22 when intrathoracic involvement is documented
- •C85.22 — Mediastinal large B-cell lymphoma: Different lymphoma entity entirely
- •C81.02 — NLPHL, intrathoracic: Different subtype